A media source with rechargeable batteries is recharged when connected via USB and when the ignition is in position I, II or the engine is running.
To facilitate the use of a USB memory stick, only store compatible formats on it. It takes a lot longer for the system to load storage media that contains anything other than compatible formats. In addition to audio, the media player also supports video playback when the device is connected via USB.
Some MP3 players have their own file systems that are not supported by the audio system.